KR102240723B1 - Controller comprising position predict unit and a control method thereof - Google Patents

Abstract

Provided are a controller capable of solving problems wherein performance degradation and stability cannot be maintained due to a time delay in a control system using a variable structure control method, and a control method of the controller. The controller comprises: a state variable calculation unit that calculates a state variable based on a position feedback of a load unit; a position prediction unit that generates the state variable for which the time delay is compensated based on an output of the state variable calculation unit and a control input of an immediately preceding sampling step; and a variable structure control unit that performs variable structure control in which a reference input from the outside and a state variable for which the time delay is compensated are input to follow the reference.

Description

Controller comprising position predicting unit and a control method thereof

The present invention relates to a controller including a position prediction unit and a control method thereof, and more particularly, to a controller capable of stably controlling a control system having a time delay, and a control method thereof.

[Explanation of nationally supported R&D]

This study was made with the support of the Ministry of SMEs World Class 300 (WC300) project (developing a robot motion control solution for flexible response to smart machines/collaborative robots, task identification number: S2563339).

The servo motor control system is a feedback control system that generates a control current input using an input command and an encoder feedback output of a plant, and makes the encoder feedback value follow a desired input command. A PID control method called Proportional-Integral-Derivative control is a representative example of a feedback control system. However, since the PID controller, which is a linear control method, is highly affected by model nonlinearity or disturbance, it has a disadvantage in that it requires a separate tuning process suitable for the type of load or driving environment.

In order to overcome this drawback, a variable structure control method, which is a kind of nonlinear control, has been proposed. The variable structure control method is a robust control method that is robust against changes in parameters or disturbances of a certain size. The variable structure control method has much better performance than the PID control method. In particular, when the variable structure control method and the disturbance compensation method are applied together, the stability of the system against disturbances is secured, and the chattering problem, which is a disadvantage of the variable structure control method. Can be reduced. By using the robustness of the above control methods, it can be easily applied to a nonlinear plant, and it is possible to implement a non-tuning nonlinear controller that does not require user input.

However, a general digital servo control system takes time for communication of an encoder and an operation required to generate a control input, and inevitably a time delay occurs. Since this time delay can be a factor that deteriorates the performance and stability of the entire system, a technique to compensate for this is very important. In the case of the servo system using the variable structure control method and the disturbance compensator, the time delay can be regarded as a generalized disturbance and the effect of the time delay can be compensated. We need a way to effectively compensate.

Y. Eun, et al., “Discrete-time Variable Structure Controller with a Decoupled Disturbance Compensator and Its Application to a CNC Servomechanism,” IEEE Trans. on Control Systems Technology, vol. 7, no. 4, pp. 414-423, 1999.

The present invention has been conceived to solve the above-described problems, and provides a controller and a control method of the controller capable of solving the problems of performance degradation and inability to maintain stability due to a time delay in a control system using a variable structure control method.

A controller according to an embodiment of the present invention includes a state variable calculation unit that calculates a state variable based on the position feedback of the load unit; A position prediction unit for generating a state variable for which a time delay is compensated based on an output of the state variable calculation unit and a control input of a previous sampling step; And a variable structure control unit for performing variable structure control to follow the reference by inputting a reference input from an external source and a state variable compensated for the time delay.

A method for controlling a controller according to another embodiment of the present invention includes the steps of, by a state variable calculation unit, calculating a state variable based on position feedback of the load unit; Generating a state variable compensated for the time delay based on the state variable and a control input of the previous sampling step; And performing variable structure control of following the reference by inputting a reference input from an external source and a state variable compensated for the time delay.

A computer program according to another embodiment of the present invention is stored in a medium to execute a method of controlling the controller by being combined with hardware.

The controller and its control method according to an embodiment of the present invention compensate for the time delay using a position prediction value in a situation in which a time delay occurs, thereby preventing deterioration of control performance and securing stability.

1 is a block diagram of a control system including a controller according to an embodiment of the present invention.
2 is a block diagram of a controller according to an embodiment of the present invention.
3A and 3B are graphs illustrating exemplary references.
4 is a graph showing a result of inputting the reference of FIGS. 3A and 3B to a conventional controller having a variable structure and disturbance compensation.
5 is a graph showing a result of inputting the reference of FIGS. 3A and 3B to a controller according to an embodiment of the present invention.
6 is a flowchart of a control method of a controller according to another embodiment of the present invention.
7 is a flow chart showing detailed steps of performing control following a reference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention described below refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in detail sufficient to enable a person skilled in the art to practice the present invention. The terms used in the present specification have selected general terms that are currently widely used as possible while considering functions, but this may vary according to the intention or custom of a technician working in the field, or the emergence of new technologies. In addition, in certain cases, there are terms arbitrarily determined by the applicant, and in this case, the meaning will be described in the description section of the corresponding specification. Therefore, terms used in the present specification should be interpreted based on the actual meaning of the term and the entire contents of the present specification, not a simple name of the term.

1 is a block diagram of a control system including a controller according to an embodiment of the present invention. Referring to FIG. 1, the control system 10 includes a controller 110 and a load unit 120.

)를 발생한다. 제어기(110)에서 발생한 제어 입력(

)은 부하부(120)에 전달된다. 부하부(120)는 전류 제어기(121), 제어 대상(122) 및 엔코더(123)를 포함한다. 먼저, 제어기(110)로부터 전류 제어기(121)로 제어 입력(

)이 전달되면, 전류 제어기(121)는 제어 입력(

)에 상응하는 구동 전류를 제어 대상(122, 또는 부하)에 제공한다. 그리고, 엔코더(123)는 예를 들어, 구동된 제어 대상(122)의 상태를 측정하여 피드백 정보(

)를 제어기(110)에 피드백으로서 제공한다. 제어기(110)는 이후의 서보 모터 제어시 수신된 피드백(

)을 참조한다. 여기서, 피드백 정보는 각변위를 기초로 생성될 수 있으나, 이에 한정되는 것은 아니며 제어 대상의 각변위(angular position) 및/또는 각속도(angular velocity)를 기초로 생성된 정보일 수도 있다. 전류 제어기(121), 모터(122) 및 엔코더(123)의 구체적인 구성 및 동작 방법은 당해 기술 분야에 널리 알려져 있으므로, 여기서는 그에 대한 설명은 생략한다.The controller 110 is a control input for the control target 122 included in the load unit 120 (

) Occurs. Control input generated from the controller 110 (

) Is transmitted to the load unit 120. The load unit 120 includes a current controller 121, a control target 122, and an encoder 123. First, a control input from the controller 110 to the current controller 121 (

) Is transmitted, the current controller 121 is a control input (

A driving current corresponding to) is provided to the control object 122 (or a load). And, the encoder 123 measures the state of the driven control object 122, for example, and feedback information (

) To the controller 110 as feedback. The controller 110 receives the feedback (

). Here, the feedback information may be generated based on an angular displacement, but is not limited thereto, and may be information generated based on an angular position and/or an angular velocity of a control target. Since the detailed configuration and operation method of the current controller 121, the motor 122, and the encoder 123 are widely known in the art, a description thereof will be omitted here.

2 is a block diagram of a controller according to an embodiment of the present invention. Referring to FIG. 2, the controller 110 of the present invention may include a variable structure control unit 111 and a state variable calculation unit 112 that can provide both a variable structure control function and a disturbance compensation function. Specifically, the variable structure control unit 111 may include a switching function calculation unit 111A, a disturbance estimation unit 111B, and a control input calculation unit 111C. In addition, the controller 110 of the present invention may further include a position prediction unit 113 for compensating for a time delay of a feedback value provided from the load unit 120.

Here, the controller 110 and each device or unit constituting the controller 110 according to the embodiments may have an aspect that is entirely hardware, or partially hardware and partially software. For example, each component of the controller 110 of the present invention refers to a combination of hardware and software driven by the hardware. The hardware may be a data processing device including a central processing unit (CPU) or another processor. In addition, software driven by hardware may refer to an executing process, an object, an executable file, a thread of execution, a program, and the like. For example, the switching function calculation unit 111 may refer to a combination of hardware and software for the same. In addition, in the present specification, each unit constituting the controller 110 is not necessarily intended to refer to separate components that are physically separated. That is, in FIG. 2, each unit of the controller 110 is shown as a separate block that is distinguished from each other, but this is functionally divided by the operation performed by the controller 110. Depending on the embodiment, some or all of the above-described units may be integrated into the same single device, or one or more units may be implemented as separate devices that are physically separated from other units. For example, each unit may be components that are communicatively connected to each other in a distributed computing environment.

First, the functions and characteristics of the variable structure control unit 111 and the state variable calculation unit 112 are described in a state in which the position prediction unit 113 is not applied, and then the present invention that appears as the position prediction unit 113 is applied. Let's further describe the technical characteristics of

)를 추종하도록 제어 입력(

)을 생성하도록 구성될 수 있다.In the system environment of the discrete time state-space equation according to Equation 1 below, the controller 110 receives an input reference (

Control input (

) Can be configured to generate.

[Equation 1]

는 상태 변수로,

는 위치 피드백,

는 속도 피드백 값이며,

는 제어기로부터 제공되는 제어 입력,

는 일반화된 외란,

는 시스템 매트릭스로

로 정의되며,

는 입력 매트릭스로

로 정의되고

는 시스템 관성이고,

는 모터의 토크 상수이며,

는 제어기의 제어 주기에 해당한다.)(here,

Is the state variable,

Position feedback,

Is the speed feedback value,

Is the control input provided from the controller,

Is a generalized disturbance,

Is the system matrix

Is defined as,

Is the input matrix

Is defined as

Is the system inertia,

Is the torque constant of the motor,

Corresponds to the control cycle of the controller.)

)는 부하부(120)의 피드백 정보(

)를 기초로 상태 변수 계산부(112)에서 계산될 수 있다. 절환 함수 계산부(111A)는 현재 상태의 절환 함수 출력(

)을 정의할 수 있다. 절환 함수 계산부(111A)는 입력되는 레퍼런스(

)와 피드백 된 부하부의 상태 변수(

)으로 구성된 절환 함수 출력(

)을 계산할 수 있다. 절환 함수 출력(

)은 하기 수학식 2와 같이 정의된다.State variable (

) Is the feedback information of the load unit 120 (

) Can be calculated in the state variable calculation unit 112 based on. The switching function calculation unit 111A outputs the switching function in the current state (

) Can be defined. The switching function calculation unit 111A is an input reference (

) And the state variable of the load part fed back (

Switching function output consisting of (

) Can be calculated. Switching function output (

) Is defined as in Equation 2 below.

[Equation 2]

는 오차 함수로,

로 정의되고,

는 절환 함수 관련 게인 매트릭스이다.)(here,

Is the error function,

Is defined as,

Is the gain matrix related to the switching function.)

)은 입력되는 레퍼런스(

)와 상기 상태 변수(

)를 기초로 정의된다.In other words, the switching function output (

) Is the input reference (

) And the above state variable (

) Is defined on the basis of.

)과 절환 함수 출력(

)에 기초하여 외란 추정값(

)을 계산할 수 있다. 외란 추정 값(

)은 하기 수학식 3과 같이 정의된다.The disturbance estimating unit 111B is the disturbance estimation gain (

) And switching function output (

) Based on the disturbance estimate (

) Can be calculated. Disturbance estimate (

) Is defined as in Equation 3 below.

[Equation 3]

는 오차 함수(

)가 슬라이딩 매니폴드로 도달하는 속도를 결정하는 파라미터,

는 포화 함수의 이득이며,

는 포화 함수의 경계층의 두께(boundary layer thickness)를 결정하는 파라미터,

는 외란 추정 이득이다.)(here,

Is the error function (

A parameter that determines the speed at which) reaches into the sliding manifold,

Is the gain of the saturation function,

Is a parameter that determines the boundary layer thickness of the saturation function,

Is the estimated gain of disturbance.)

)을 0으로 만들기 위한, 외란 추정부(111B)가 추정한 외란 추정 값(

)과 제어 입력 계산부(111C)의 제어 입력(

)이 정의될 수 있다. 제어 입력 계산부는 절환 함수 출력(

), 상기 외란 추정 값(

) 및 상기 상태 변수(

)에 기초하여 현재 상태의 제어 입력(

)을 계산한다. 현재 상태의 제어 입력(

)은 하기 수학식 4와 같이 정의된다.In the state space equation of Equation 1, the switching function output (

) To be 0, the disturbance estimation value estimated by the disturbance estimation unit 111B (

) And the control input of the control input calculation unit 111C (

) Can be defined. The control input calculation unit outputs the switching function (

), the estimated disturbance value (

) And the state variable (

) Based on the control input of the current state (

) Is calculated. Control input in the current state (

) Is defined as in Equation 4 below.

[Equation 4]

)에서

는 상기 외란 추정 값(

)을 제외한 값이다.)(Here, control input(

)in

Is the estimated disturbance value (

It is the value excluding ).)

)은 상기 절환 함수 출력(

), 상기 외란 추정 값(

), 외부로부터 입력되는 레퍼런스(

) 및 상기 상태 변수 생성부로부터 출력된 상태 변수(

)를 기초로 정의된다. 따라서, 부하부(120)의 엔코더(123)의 통신, 제어 입력을 생성하는 데에 필요한 연산 등에 시간이 소요되어 필연적으로 시간 지연이 발생하는 경우 전체 시스템의 성능 및 안정성의 저하가 야기될 수 있다. In other words, the control input of the current state (

) Is the switching function output (

), the estimated disturbance value (

), reference input from the outside (

) And the state variable output from the state variable generator (

) Is defined on the basis of. Therefore, if time is required for communication of the encoder 123 of the load unit 120 or an operation required to generate a control input, and inevitably a time delay occurs, the performance and stability of the entire system may be deteriorated. .

)의 시간 지연을 보상하기 위한 위치 예측부(113)를 더 포함할 수 있으며, 시간 지연의 보상을 통해 전체 시스템의 성능 저하와 안정성 저하를 방지할 수 있다. 이하, 위치 예측부(113)를 적용한 본 실시예의 제어기(100)에 대해 보다 상세히 설명하도록 한다.Here, the controller 100 according to an embodiment of the present invention provides feedback information provided by the load unit 120 (

A position prediction unit 113 for compensating for a time delay of) may be further included, and a decrease in performance and stability of the entire system may be prevented by compensating for the time delay. Hereinafter, the controller 100 of the present embodiment to which the position prediction unit 113 is applied will be described in more detail.

The discrete time state-space equation of the present invention can be expressed as Equation 5 using Equations 1 and 4 above.

[Equation 5]

는 실제 외란(

)과 외란 추정값(

)의 차이를 나타낸다.)(here,

Is the actual disturbance (

) And the disturbance estimate (

) Represents the difference.)

)의 변화율이 충분히 느림을 가정할 경우, 실제 외란(

)과 외란 추정값(

)의 차이를 0으로 볼 수 있다(

). Disturbance in the above equation (

Assuming that the rate of change of) is slow enough, the actual disturbance (

) And the disturbance estimate (

The difference between) can be seen as 0 (

).

Therefore, the discrete time state-space equation in which the disturbance is sufficiently compensated can be expressed as Equation 6 below.

[Equation 6]

)와 오일러 미분 방법을 활용해 각속도 피드백 정보를 계산할 수 있고, 상태 변수(

)는 하기 수학식 7와 같은 상태 변수로 나타낼 수 있다.The state variable calculation unit 112 includes position feedback information of the load unit 120 (

) And Euler's differential method can be used to calculate the angular velocity feedback information, and the state variable (

) Can be expressed as a state variable such as Equation 7 below.

[Equation 7]

는 샘플링 시간을 의미하고,

와

는 각각 각변위와 각속도를 나타낸다.)(here,

Means the sampling time,

Wow

Represents angular displacement and angular velocity, respectively.)

)와 이전 샘플링 단계의 제어 입력(

)에서 외란 추정값(

)을 제외한 값(

)에 기초하여 시간 지연이 있는 시스템의 위치를 계산할 수 있으며, 시간 지연이 보상된 상태 변수(

)를 생성할 수 있다. 시간 지연이 보상된 상태 변수(

)는 하기 수학식 8과 같이 나타낼 수 있다. When performing digital control, it takes time for encoder communication and control operation, so a time delay may inevitably occur in the feedback signal. The position prediction unit 113 may compensate for a delay corresponding to one sampling time in the load unit 120 by using Equations 6 and 7 above. That is, the position prediction unit 113 is a state variable (

) And the control input of the previous sampling step (

) To the disturbance estimate (

Values excluding (

), the position of the system with the time delay can be calculated, and the time delay compensated state variable (

) Can be created. The time delay compensated state variable (

) Can be expressed as in Equation 8 below.

[Equation 8]

는 각변위 추정값,

는 각속도 추정값을 나타낸다.)(here,

Is the estimated value of the angular displacement,

Represents the angular velocity estimate.)

)는

,

와

만을 이용하여 표현된 것으로, 이는 단순한 대수 계산만을 수행하여 시간 지연이 보상된 위치 피드백의 상태 변수를 계산한 것이다. 즉, 극점이 없는 유한 임펄스 응답 필터 형태로, 입력-출력 안정성(Bounded-Input Bounded-Output stable)이 항상 보장될 수 있다.Here, in Equation 8, the time delay is compensated for the state variable (

) Is

,

Wow

It is expressed using only, and this is a calculation of the state variable of the position feedback compensated for the time delay by performing only a simple logarithmic calculation. That is, in the form of a finite impulse response filter without poles, Bounded-Input Bounded-Output stable can always be guaranteed.

)를 사용하지 않고 시간 지연이 보상된 위치 피드백의 상태 변수(

)을 사용하여 가변 구조 제어를 수행할 수 있다. 즉, 상태 변수(

)를 활용해 계산했던 종래의 수학식 2 및 수학식 4에서 상태 변수 항만 시간 지연이 보상된 위치 피드백의 상태 변수(

)로 변경되어 별도의 수식 변화 없이 전체적인 제어가 수행될 수 있다. 즉, 본 실시예에 따른 제어기(110)는 상기 수학식 1에 따른 이산 시간 상태 공간 방정식의 시스템 환경에서, 입력 받은 레퍼런스(

)를 추종하도록 제어 입력(

)을 생성하도록 구성될 수 있다.That is, the controller 110 according to the present embodiment includes the above-described position predictor 113 and uses a simple position feedback as in the related art.

), and the time delay is compensated for the state variable of the position feedback (

) Can be used to perform variable structure control. That is, the state variable (

) In the conventional Equations 2 and 4 calculated using the state variable of the position feedback in which the port time delay is compensated (

), so that overall control can be performed without a separate formula change. That is, in the system environment of the discrete time state-space equation according to Equation 1, the controller 110 according to the present embodiment receives an input reference (

Control input (

) Can be configured to generate.

)와 시간 지연이 보상된 상태 변수(

)으로 구성된 절환 함수 출력(

)을 계산할 수 있다. 절환 함수 출력(

)은 하기 수학식 9와 같이 정의된다.In addition, the switching function calculation unit 111A is an input reference (

) And the time delay compensated state variable (

Switching function output consisting of (

) Can be calculated. Switching function output (

) Is defined as in Equation 9 below.

[Equation 9]

는 오차 함수로,

로 정의되고,

는 절환 함수 관련 게인 매트릭스이다.)(here,

Is the error function,

Is defined as,

Is the gain matrix related to the switching function.)

)를 하기 수학식 10과 같이 계산하여, 부하부(120)에 출력한다.In addition, the control input calculation unit 111C is a control input in the current state (

) Is calculated as in Equation 10 below, and output to the load unit 120.

[Equation 10]

The controller 100 according to an embodiment of the present invention may provide a result of compensating for a time delay by using an equation in which only a state variable is changed without affecting the stability guaranteed in a conventional controller. Accordingly, the stability of the system is improved, and the gain of the controller is further increased to have a higher control performance. Hereinafter, an embodiment of a controller according to an embodiment of the present invention will be described.

[Example]

)는 0.125 ms이다. 제어기의 각 파라미터는 하기 표 1과 같이 설정되었다.The control target is a 400W AC servo motor, which is mounted on an industrial belt drive system. Sampling cycle (

) Is 0.125 ms. Each parameter of the controller was set as shown in Table 1 below.

[Table 1]

) 및 각속도(angular velocity,

)이다. 도 3는 예시적인 레퍼런스를 도시한 그래프이다. 도 3a는 각각 제어 대상의 각변위에 대한 레퍼런스, 도 3b는 제어 대상의 각속도에 대한 레퍼런스를 도시한 그래프이다.The reference to the control object is the angular position of the control object.

) And angular velocity,

)to be. 3 is a graph showing an exemplary reference. 3A is a graph showing a reference for an angular displacement of a control target, and FIG. 3B is a graph showing a reference for an angular velocity of a control target.

4 is a graph showing a result of inputting the reference of FIGS. 3A and 3B to a conventional controller. 4A shows an angular displacement error, FIG. 4B shows an angular velocity, and FIG. 4C shows a change in a current command value for a reference.

5 is a graph showing a result of inputting the reference of FIGS. 3A and 3B to the controller according to the present embodiment. 5A shows an angular displacement error, FIG. 5B shows an angular velocity, and FIG. 5C shows a change in a current command value for a reference.

Comparing FIGS. 4 and 5, it can be seen that when the belt drive system is driven by using a conventional controller, the system has insufficient stability margin and thus resonance occurs in the system. In contrast, in the case of the controller according to the present embodiment, it can be seen that the stability margin of the system is improved and thus the controller is driven without resonance.

That is, the controller 100 according to the present embodiment can provide stable servo control by compensating for an effect of the time delay in a situation where there is a time delay. In addition, it is possible to provide robustness while maintaining the robustness, which is the advantage of the variable structure control method and the disturbance estimation unit, and excellent tracking performance structure.

Hereinafter, a method of controlling a controller according to another embodiment of the present invention will be described. The controller may be the controller 110 of FIGS. 1 to 5 described above, and FIGS. 1 to 5 may be referred to for explanation of the present embodiment.

6 is a flowchart of a control method of a controller according to another embodiment of the present invention. 7 is a flow chart showing detailed steps of performing control following a reference.

6 and 7, a control method of a controller according to another embodiment of the present invention includes calculating a state variable based on position feedback of a load (S100); Generating a state variable compensated for the time delay based on the state variable and a control input of the previous sampling step (S200); And performing a variable structure control following the reference by inputting a reference input from an external source and a state variable compensated for the time delay (S300).

First, a state variable is calculated based on the position feedback of the load unit (S100).

)와 오일러 미분 방법을 활용해 각속도 피드백 정보를 계산할 수 있고, 상태 변수(

)는 하기 수학식 7와 같은 상태 변수로 나타낼 수 있다.The state variable calculation unit 112 includes position feedback information of the load unit 120 (

) And Euler's differential method can be used to calculate the angular velocity feedback information, and the state variable (

) Can be expressed as a state variable such as Equation 7 below.

[Equation 7]

는 샘플링 시간을 의미하고,

와

는 각각 각변위와 각속도를 나타낸다.)(here,

Means the sampling time,

Wow

Represents angular displacement and angular velocity, respectively.)

The state variable may be composed of a differential value of the position feedback and the position feedback.

A state variable compensated for the time delay is generated based on the state variable and the control input of the previous sampling step (S200).

)와 이전 샘플링 단계의 제어 입력(

)에서 외란 추정값(

)을 제외한 값(

)에 기초하여 시간 지연이 있는 시스템의 위치를 계산할 수 있으며, 시간 지연이 보상된 상태 변수(

)를 생성할 수 있다. 시간 지연이 보상된 상태 변수(

)는 하기 수학식 8과 같이 나타낼 수 있다.The position prediction unit 113 is a state variable (

) And the control input of the previous sampling step (

) To the disturbance estimate (

Values excluding (

), the position of the system with the time delay can be calculated, and the time delay compensated state variable (

) Can be created. The time delay compensated state variable (

) Can be expressed as in Equation 8 below.

[Equation 8]

는 각변위 추정값,

는 각속도 추정값을 나타낸다.)(here,

Is the estimated value of the angular displacement,

Represents the angular velocity estimate.)

)는

,

와

만을 이용하여 표현된 것으로, 이는 단순한 대수 계산만을 수행하여 시간 지연이 보상된 위치 피드백의 상태 변수를 계산한 것이다. 즉, 극점이 없는 유한 임펄스 응답 필터 형태로, 입력-출력 안정성(Bounded-Input Bounded-Output stable)이 항상 보장될 수 있다.Here, in Equation 8, the time delay is compensated for the state variable (

) Is

,

Wow

It is expressed using only, and this is a calculation of the state variable of the position feedback compensated for the time delay by performing only a simple logarithmic calculation. That is, in the form of a finite impulse response filter without poles, Bounded-Input Bounded-Output stable can always be guaranteed.

A variable structure control for following the reference is performed by inputting a reference input from an external source and a state variable compensated for the time delay (S300).

)를 추종하도록 제어 입력(

)을 생성하도록 구성될 수 있다.In the system environment of the discrete time state-space equation according to Equation 1 below, the controller 110 according to the present embodiment receives an input reference (

Control input (

) Can be configured to generate.

[Equation 1]

는 상태 변수로,

는 위치 피드백,

는 속도 피드백 값이며,

는 제어기로부터 제공되는 제어 입력,

는 일반화된 외란,

는 시스템 매트릭스로

로 정의되며,

는 입력 매트릭스로

로 정의되고

는 시스템 관성이고,

는 모터의 토크 상수이며,

는 제어기의 제어 주기에 해당한다.)(here,

Is the state variable,

Position feedback,

Is the speed feedback value,

Is the control input provided from the controller,

Is a generalized disturbance,

Is the system matrix

Is defined as,

Is the input matrix

Is defined as

Is the system inertia,

Is the torque constant of the motor,

Corresponds to the control cycle of the controller.)

Here, the step of performing the variable structure control (S300) may include calculating a difference between the reference and the output of the state variable compensated for the time delay, and calculating a switching function output based on the difference (S310); Calculating an estimated disturbance value based on the switching function output (S320); And calculating a control input of the current sampling step based on the reference, the switching function output, the disturbance estimation value, and a state variable compensated for the time delay (S330).

)와 시간 지연이 보상된 상태 변수(

)으로 구성된 절환 함수 출력(

)을 계산할 수 있다. 절환 함수 출력(

)은 하기 수학식 9과 같이 정의된다.Calculating a difference between the reference and the output of the state variable compensated for the time delay, and calculating the switching function output based on the difference (S310) is performed by the switching function calculating unit 111A. In addition, the switching function calculation unit 111A is an input reference (

) And the time delay compensated state variable (

Switching function output consisting of (

) Can be calculated. Switching function output (

) Is defined as in Equation 9 below.

[Equation 9]

는 오차 함수로,

로 정의되고,

는 절환 함수 관련 게인 매트릭스이다.)(here,

Is the error function,

Is defined as,

Is the gain matrix related to the switching function.)

)과 절환 함수 출력(

)에 기초하여 외란 추정값(

)을 계산할 수 있다. 외란 추정 값(

)은 하기 수학식 3과 같이 정의된다.The step (S320) of calculating a disturbance estimation value based on the switching function output is performed by the disturbance estimation unit 111B. The disturbance estimating unit 111B is the disturbance estimation gain (

) And switching function output (

) Based on the disturbance estimate (

) Can be calculated. Disturbance estimate (

) Is defined as in Equation 3 below.

[Equation 3]

는 오차 함수(

)가 슬라이딩 매니폴드로 도달하는 속도를 결정하는 파라미터,

는 포화 함수의 이득이며,

는 포화 함수의 경계층의 두께(boundary layer thickness)를 결정하는 파라미터,

는 외란 추정 이득이다.)(here,

Is the error function (

A parameter that determines the speed at which) reaches into the sliding manifold,

Is the gain of the saturation function,

Is a parameter that determines the boundary layer thickness of the saturation function,

Is the estimated gain of disturbance.)

)를 하기 수학식 10과 같이 계산하여, 부하부(120)에 출력할 수 있다.The step (S330) of calculating the control input of the current sampling step based on the reference, the switching function output, the disturbance estimation value, and the time delay compensated state variable (S330) is performed by the control input calculation unit 111C. The control input calculation unit 111C is the control input in the current state (

) Can be calculated as in Equation 10 below and output to the load unit 120.

[Equation 10]

The control method of a controller according to another embodiment of the present invention may provide a result of compensating for a time delay by using an equation in which only a state variable is changed without affecting the stability guaranteed in a conventional controller. Accordingly, the stability of the system is improved, and the gain of the controller is further increased to have a higher control performance.

The operation by the control method of the controller according to the above-described embodiments may be implemented at least partially as a computer program and recorded on a computer-readable recording medium. A computer-readable recording medium in which a program for implementing an operation of a controller control method according to the embodiments is recorded and includes all types of recording devices in which data that can be read by a computer is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tapes, floppy disks, and optical data storage devices. In addition, the computer-readable recording medium may be distributed over a computer system connected through a network, and computer-readable codes may be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing this embodiment may be easily understood by those of ordinary skill in the art to which this embodiment belongs.

Although described above with reference to examples, the present invention should not be construed as being limited by these examples or drawings, and those skilled in the art will be able to understand the spirit and scope of the present invention described in the following claims. It will be appreciated that various modifications and changes can be made to the present invention without departing from.

10: control system
110: controller
111: switching function calculation unit
112: state variable calculation unit
113: position prediction unit
120: load
121: current controller
122: control target
123: encoder

Claims (15)

A state variable calculation unit that calculates a state variable based on the position feedback of the load unit;
A position prediction unit for generating a state variable for which a time delay is compensated based on an output of the state variable calculation unit and a control input of a previous sampling step; And
A variable structure control unit for performing variable structure control for following the reference by inputting a reference input from an external source and a state variable compensated for the time delay,
The variable structure control unit,
A switching function calculation unit calculating a difference between the reference and an output of the state variable compensated for the time delay, and calculating a switching function output based on the difference;
A disturbance estimating unit that calculates a disturbance estimation value based on the switching function output; And
And a control input calculator configured to calculate a control input of a current sampling step based on the reference, the switching function output, the disturbance estimation value, and a state variable compensated for the time delay. delete The method of claim 1,
The switching function output is defined based on a reference input from an external source and a state variable compensated for the time delay. The method of claim 1,
The disturbance estimation value is defined based on the switching function output and the disturbance estimation gain. The method of claim 1,
The control input is defined based on the switching function output, the disturbance estimation value, a reference input from the outside, and a state variable compensated for the time delay. The method of claim 1,
Wherein the state variable is composed of a differential value of the position feedback and the position feedback. The method of claim 1,
The state variable compensated for the time delay is calculated by reflecting a system model based on the state variable and an output of the immediately preceding sampling step of the control input calculator. Calculating a state variable based on the position feedback of the load unit;
Generating a state variable compensated for the time delay based on the state variable and a control input of the previous sampling step; And
Comprising the step of performing variable structure control to follow the reference by inputting a reference input from an external source and a state variable compensated for the time delay,
The step of performing the variable structure control,
Calculating a difference between the reference and the output of the state variable compensated for the time delay, and calculating a switching function output based on the difference;
Calculating a disturbance estimate based on the switching function output; And
And calculating a control input of a current sampling step based on the reference, the switching function output, the disturbance estimation value, and a state variable compensated for the time delay. delete The method of claim 8,
The control method of a controller, characterized in that the switching function output is defined based on a reference input from an external source and a state variable compensated for the time delay. The method of claim 8,
The disturbance estimation value is defined based on the switching function output and the disturbance estimation gain. The method of claim 8,
The control input is defined based on the switching function output, the disturbance estimation value, a reference input from the outside, and a state variable compensated for the time delay. The method of claim 8,
The state variable is a control method of a controller, characterized in that consisting of a differential value of the position feedback and the position feedback. The method of claim 8,
The time delay-compensated state variable is calculated by reflecting a system model based on the state variable and an output of the immediately preceding sampling step of the control input calculator. A computer program combined with hardware and stored in a medium to execute the control method of a controller according to any one of claims 8 and 10 to 14.

Images